OpenBeam Heavy Duty Coupler
by jcaywood, published
I was working on an OB1.4 OpenBeam printer hardware kit for a friend and mis-cut one of the OpenBeam pieces. Since OpenBeam was having stock issues I had to fix the problem so I created this very strong OpenBeam coupler. The walls are over 8mm thick and it fits the OpenBeam very closely. It has bolt holes for 16 3mm screws which will vary in length depending on if you use washers or washers and lock washers. This piece when printed at 100% infill is extremely strong and could even be used to couple 1 meter lengths of OpenBeam if required.
Print the part at 100% infill and clean out the screw holes of support if needed. Drill the holes to between 3 and 3.2mm.
Insert each piece of OpenBeam halfway into the coupler then slide nuts into the OpenBeam and secure with 3mm screws/bolts with washers, lockwashers or a combination of the two.
The required bolt length will vary depending on which you use. The wall thickness is 8+mm, a lockwasher is 1mm and a washer is about 0.5mm plus you'll need another 2-4mm of bolt to go into the extrusion, 10-14mm bolts should do the trick.
Source file is in Autocad A123D (beta)
I'm fairly new to uploading objects, but this piece was printed on my highly calibrated printer which has about .005mm or less of error per mm printed and it fit fine.